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Red supergiant star
Red supergiants are supergiant stars of spectral type K-M and a luminosity class of I. They are the largest stars in the universe in terms of physical size, although they are not the most massive. Stars with more than about 10 solar masses, after burning their hydrogen become red supergiants during their helium-burning phase. These stars have very cool surface temperatures (3500-4500 K), and enormous radii. The four largest known red supergiants in the Galaxy are Mu Cephei, KW Sagitarii, V354 Cephei, and KY Cygni, which all have radii about 1500 times that of the sun (about 7 astronomical units, or 7 times as far as the Earth is from the sun). The radius of most red giants is between 200 and 800 times that of the sun, which is still enough to reach from the sun to Earth and beyond.
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Space & Time News
December 26, 2025
Dec. 25, 2025 Scientists are digging into the hidden makeup of carbon-rich asteroids to see whether they could one day fuel space exploration—or even be mined for valuable resources. By analyzing rare meteorites ...
Dec. 22, 2025 Astronomers have uncovered a massive hidden planet and a rare “failed star” by combining ultra-precise space data with some of the sharpest ground-based images ever taken. Using the Subaru Telescope in Hawaiʻi, the OASIS survey tracked subtle ...
Dec. 19, 2025 Gravitational waves from black holes may soon reveal where dark matter is hiding. A new model shows how dark matter surrounding massive black holes leaves detectable fingerprints in the waves recorded by future space ...
Dec. 17, 2025 Researchers have shown that quantum signals can be sent from Earth up to satellites, not just down from space as previously believed. This breakthrough could make global quantum networks far more powerful, affordable, and ...
Dec. 6, 2025 SQUIRE aims to detect exotic spin-dependent interactions using quantum sensors deployed in space, where speed and environmental conditions vastly improve sensitivity. Orbiting sensors tap into ...
Dec. 3, 2025 Earth’s orbit is getting crowded with broken satellites and leftover rocket parts. Researchers say the solution is to build spacecraft that can be repaired, reused, or recycled instead of abandoned. They also want new tools to collect old debris ...
Dec. 2, 2025 A UC Irvine team uncovered a never-before-seen quantum phase formed when electrons and holes pair up and spin in unison, creating a glowing, liquid-like state of matter. By blasting a custom-made material with enormous magnetic fields, the ...
Nov. 23, 2025 A massive solar storm in May 2024 gave scientists an unprecedented look at how Earth’s protective plasma layer collapses under intense space weather. With the Arase satellite in a perfect observing position, researchers watched the plasmasphere ...
Nov. 21, 2025 New observations show that asteroid 1998 KY26 is a mere 11 meters across and spinning twice as fast as previously thought. The discovery adds complexity to Hayabusa2’s 2031 mission but also heightens scientific interest. The asteroid’s ...
Nov. 17, 2025 Scientists built a tiny clock from single-electron jumps to probe the true energy cost of quantum timekeeping. They discovered that reading the clock’s output requires vastly more energy than the clock uses to function. This measurement process ...
Nov. 16, 2025 Researchers combined deep learning with high-resolution physics to create the first Milky Way model that tracks over 100 billion stars individually. Their AI learned how gas behaves after supernovae, removing one of the biggest computational ...
Nov. 16, 2025 Dark matter may be invisible, but scientists are getting closer to understanding whether it follows the same rules as everything we can see. By comparing how galaxies move through cosmic gravity wells to the depth of those wells, researchers found ...
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Dec. 26, 2025 Astronomers have decoded the hidden past of a distant red giant star by listening to tiny vibrations in its light, revealing clues of a dramatic cosmic history. The star, which quietly orbits a ...
Dec. 26, 2025 When Earth was a molten inferno, water may have been locked safely underground rather than lost to space. Researchers discovered that bridgmanite ...
Dec. 25, 2025 Scientists have discovered a giant cosmic filament where galaxies spin in sync with the structure that holds them together. The razor-thin chain of galaxies sits inside a much larger filament that ...
Dec. 25, 2025 This Christmas, astronomers are highlighting a spectacular region of space that looks remarkably like a glowing holiday tree. Known as NGC 2264, this distant star-forming region sits about 2,700 ...
Dec. 22, 2025 Black holes are among the most extreme objects in the universe, and now scientists can model them more accurately than ever before. By combining Einstein’s gravity with realistic behavior of light ...
Dec. 21, 2025 By studying tiny distortions in the shapes of distant galaxies, scientists mapped dark matter and dark energy across one of the largest sky surveys ever assembled. Their results back the standard ...
Dec. 20, 2025 An instrument aboard NASA’s Europa Clipper spacecraft captured rare ultraviolet observations of an interstellar comet while Earth-based telescopes were blinded by the Sun. The spacecraft’s unique ...
Dec. 20, 2025 For years, scientists thought Saturn’s moon Titan hid a global ocean beneath its frozen surface. A new look at Cassini data now suggests something very different: a thick, slushy interior with ...
Dec. 19, 2025 Cosmic “touchdown airbursts” — explosions of comets or asteroids above Earth’s surface — may be far more common and destructive than previously thought, according to new research. Unlike ...
Dec. 18, 2025 Astronomers have detected spacetime itself being dragged and twisted by a spinning black hole for the first time. The discovery, seen during a star’s violent destruction, confirms a prediction made ...